The present invention relates to a disk cartridge for accommodating in a cartridge body an optical disk, magneto-optic disk, or other disk on which data signals are recorded. More particularly, the present invention relates to a disk cartridge for protecting the disk accommodated in the cartridge body.
In the past, optical disks, magneto-optic disks, and other disks on which data signals have been recorded have been accommodated in disk cartridges so as to prevent dust etc. from adhering to the disks or scratches being made on the main surfaces of the disks where the data signal recording portions are formed during storage, or fingerprints etc. being made on the surface of the disks by direct; contact of the fingers on the disks when loading them into the recording and/or reproduction apparatuses, and further to facilitate loading of the disks in the recording and/or reproduction apparatuses. That is, the disks have been rotatably accommodated in the disk cartridges and have been handled while accommodated in the disk cartridges.
This type of disk cartridge 101, as shown in FIG. 1 and FIG. 2, is provided with a cartridge body 104 formed by mating an upper and lower half 102 and 103 formed by molding a plastic material into substantially square shapes and connecting them near their corners by screws 131. This cartridge body 104 accommodates an optical disk, magneto-optic disk, or other disk 105 serving as the recording media for the data signals. The screws 131 for connecting the upper and lower halves 102 and 103 are screwed through the screwing portions 136 and 137 provided at the upper half 103. At the peripheries of the mateable upper and lower halves 102 and 103 are integrally formed walls 132 and 133 which may be mated to constitute the circumferential walls of the cartridge body 104.
In the cartridge body 104 is formed a disk accommodating space 106 of a circular shape of a diameter larger than the outer diameter of the disk 105 and a thickness greater than the thickness of the disk 105. The disk 105 is rotatably accommodated a disk 106. The disk accommodating space 106 is comprised by mating the arc-shaped ribs 134 and 135 projecting from the facing inner surfaces of the upper and lower halves 102 and 103 so as to be inscribed by the walls 132 and 133 formed at the peripheries of the upper and lower halves 102 and 103.
At the top and bottom surfaces of the cartridge body 104 from the center to the front are openings 107 and 108 for allowing the approach of a disk table 121 of a disk rotating mechanism arranged inside the recording and/or reproduction apparatus in which the disk cartridge 101 is loaded and a pickup apparatus constituting the recording and reproduction means for recording and/or reproducing predetermined data signals to and/or from the disk 105 being rotated by the disk table rotation mechanism. These openings 107 and 108 are closed by the shutter member 109 provided slidably on the cartridge body 104 and are opened only during use when the disk cartridge 101 is loaded in the recording and/or reproduction apparatus. Entry of dust etc. into the cartridge body 104 is prevented during non-use, contact of the fingers with the signal recording region 105a of the disk 105 is prevented, and recording and reproduction error of the data signals caused by deposition of dust or fingerprints on the signal recording region 105a are prevented.
Further, at the centers of the two main surfaces of the disk substrate 115 on which the signal recording region 105a of the disk 105 is formed and made of mainly a plastic substrate are provided hubs 111 having center holes 110 for engagement with a center spindle 122 provided at the center of the disk table as shown in FIG. 1. These hubs 111 are comprised of ring members 112 comprised of plastic and metal plates 113 having magnetic characteristics attached integrally to the ring members 112.
The disk cartridge 101 configured in this way is positioned for loading by engaging a positioning hole (not shown) formed in the main surface at the bottom side of the cartridge body 104 with a positioning pin provided in the recording and/or reproduction apparatus and then is loaded in the cartridge loader in the recording and/or reproduction apparatus. The disk 105 accommodated in the disk cartridge 101 loaded in the cartridge loader, as shown in FIG. 2, is loaded on the disk table 121. The disk table 121 has at its center a center spindle 122 for engaging with a center hole provided in a hub 111 of the disk 105 and uses the top surface of its outer circumference as the disk receiving surface 123 supporting the non-signal recording region 105b of the disk 5 positioned at the outer periphery of the hub 111. Further, at the inner circumference of the disk table 121, a ring-shaped magnet 124 for magnetically attracting the metal plate 113 attached to the hub 111 is provided around the center spindle 122. By bringing the center into register with the center spindle 122 and providing the ring-shaped magnet 124, a uniform magnetic field is applied to the hub 111 of the disk 105 loaded on the disk table 121.
Note that the disk table 121 is designed so that when supporting the disk 105, the signal recording region 105a faces the pickup device, so is made smaller in diameter than the non-signal recording region 105b provided at the inner circumference of the disk substrate 115.
Further, the disk cartridge 101 that rotatably accommodates the disk 105 is provided with a disk support 116 projecting out from the inner surface of the cartridge body 104 so as to prevent the disk 105 and the cartridge body 104 from coming into sliding contact, and to prevent the signal recording region 105a of the disk 105 from being scratched during transport etc. This disk support 116 is formed so as to surround the periphery of the disk table entry openings 107b, 108b formed at the center of the cartridge body 104 connected to the recording and reproduction openings 107a and 108a of the openings 107 and 108 which the pickup device approaches. The disk support 116 formed at this position supports the non-signal recording region 105b at the inner circumference portion of the disk 105 at the top surface and keeps the signal recording region 105a of the disk 105 and the inner surface of the cartridge body 104 from coming into contact.
A disk cartridge 101 configured in this way may be handled alone and used loaded into a recording and/or reproduction apparatus one at a time. Sometimes, however disks are used and stored in a recording and/or reproduction apparatus that has a disk exchange mechanism which is provided with a storage unit having with a plurality of cartridge storage portions that selectively takes out the plurality of disk cartridges 101 stored in the storage unit for recording and/or reproduction of the data signals. The recording and/or reproduction apparatus provided with such a disk exchange mechanism is able to exchange disk cartridges 101 for recording and/or reproduction of data signals by selectively taking out a plurality of disk cartridges 101 stored in the storage unit and recording and/or reproducing the data signals, which enables a large volume of data signals to be easily and continuously recorded and/or reproduced.
With a recording and/or reproduction apparatus provided with a disk exchange mechanism, however, to make it possible to record and/or reproduce data signals continuously with respect to a plurality of disk cartridges 101 without large time intervals, it is necessary to transport the cartridges between the storage unit and the cartridge loader at a high speed. That is, it is necessary to exchange the disk cartridges 101 at an extremely high speed. If the disk cartridges are transported at a high speed, a large shock will end up being given to the disk cartridges. As a result, the disks 5 accommodated rotatably in the cartridge bodies 4 will shake in the cartridge bodies 4 and the disks 105 and the disk supports 116 supporting the disks 105 will end up repeatedly striking each other.
Further, the cartridge body 104 for accommodating the disk 105 is formed by a plastic having excellent shapeability and sufficient mechanical strength, such as a polycarbonate resin. On the other the disk 105, in consideration of the resistance to humidity, resistance to heat, etc., has the disk substrate 115, on which the recording film constituting the signal recording layer is provided, that is formed by a polycarbonate resin. In this way, even when similar materials are used for the material constituting the cartridge body 104 and the material constituting the disk substrate 115, with a disk cartridge 101 which supports the disk 105 by a disk support 116 provided integrally on the inner surface of the cartridge body 104 by the same material as the material constituting the cartridge body 104, frequent sliding contact between the disk 105 and the cartridge support 116 during transport for exchange etc. will sometimes result in ring-like scratches on the disk 105. Further, the surface of the disk support 116 provided on the cartridge body 104 will sometimes become worn.
Further, the surface of the disk 105 to be accommodated in the disk cartridge 101 is formed to be generally smooth and the disk support surface of the disk support 116 is formed as a smooth surface of a certain width. Accordingly, the area of contact of the disk 105 and the disk support 116 becomes large. The disk 105 rotatably accommodated in the disk cartridge 101 can move within a certain range in the cartridge body 104. Therefore, when a shock is applied to the disk cartridge 101 during transport such as exchange and the disk 105 shakes in the cartridge body 104 and engages in repeated sliding contact with the disk support 116, the scratching and wear of the surface of the disk 105 and the disk support surface of the disk support 116 will become great and the generation of dust will become severe.
When this dust is generated and accumulates at the inside of the cartridge body, the dust will adhere to the signal recording regions of the disk. If dust adheres to the signal recording regions, then losses will occur in the recording and/or reproduction of the data signals on the disk 5.
In particular, this problem is serious when the disk accommodated in the disk cartridge is an optical disk. The optical beam emitted from the optical head device will be prevented from reaching the recording layer due to the dust adhering on the optical disk, the rise of temperature of the recording layer at the portion irradiated by the optical beam will be hindered, the amount of light returning from the recording layer will be reduced, and the S/N ratio at the time of reproduction will end up deteriorating. Further, the adhesion of dust on the object lens of the optical head can also make recording and/or reproduction of the data signals completely impossible.
Further, a recording and reproduction apparatus using a rewritable magneto-optic disk as a recording medium adopts a reproduction system detecting the signals recorded on the magneto-optic disk by the minute rotation of the linear polarization plane of the optical beam irradiated on the magneto-optic disk, so the generation of dust becomes a serious problem. That is, if dust adheres to the signal recording region of the magneto-optic disk, sometimes production of the data signals becomes completely impossible.
Therefore, a disk cartridge, that prevents the generation of dust caused by wear due to the sliding contact between the disk and cartridge body, such as the configuration of FIG. 3, has been proposed. The disk cartridge 201 shown in FIG. 3 has a ring-shaped sheet 114 of superior lubricity adhered by an adhesive etc. to the non-signal recording region 105 provided at the inner circumference of the disk 105 supported by the disk support 116 provided at the cartridge body 104.
The disk 105 accommodated in the disk cartridge 201 is supported via the sheet 114 having the lubricity by the disk support 116 which is formed so as to surround the peripheries of the disk table entry openings 107b and 108b in the openings 107 and 108 formed in the cartridge body 104.
By providing the sheet 114 with superior lubricity at the portion supported by the disk support 116 in this way, it is possible to suppress the generation of dust caused by the sliding contact of the disk 105 and the disk support 116.
However, when adhering a sheet 114 of such superior lubricity to the disk 105, a special punching die is required for punching the sheet material into that shape, and further a step of adhering the sheet material becomes necessary in the process of production of the disk 105, so the production of the disk cartridge becomes complicated and the production costs end up being made higher. In particular, it is extremely difficult to bring the entire surface of the ring-shaped sheet 114 into close contact with the disk 105 for even adhesion.
Further, as shown in FIG. 4, there has been proposed a disk cartridge where a disk support member, comprised of a polyacetal resin, which is superior in lubricity, is attached by bonding or ultrasonic welding to the entire disk support surface of the disk support 116 which projects out from the cartridge body 104 and supporting the disk 105.
With such a disk cartridge, it is necessary to form a disk support member 117 corresponding in shape to the disk support 116 by molding the polyacetal resin, so it is necessary to prepare a special mold for making the disk support member 117. Accordingly, the production of the disk cartridge becomes complicated and the production costs end up being made higher. In particular, it is difficult to bring all of the surface of a continuous disk support member into close contact with the disk support 116 for attachment and there is a concern over an inability to support the disk 105 stably.
The object of the present invention is to provide a disk cartridge which prevents scratches from being made on the disk accommodated in the cartridge body and wear of the disk support provided at the cartridge body and also prevents the generation of dust due to the wear during sliding contact of the cartridge body and the disk and thereby is free from the generation of losses of data signals during recording and/or reproduction.
Another object of the present invention is to provide a disk cartridge which facilitates the attachment of the disk support member to the disk support and thereby enables reliable attachment.
Still another object of the present invention is to enable the easy production of a disk cartridge able to prevent scratches on the disk and wear of the disk support provided on the cartridge body and able to prevent the generation of dust due to wear and to provide the same inexpensively.
The disk cartridge according to the present invention, proposed so as to achieve the above objects, is provided with a cartridge body which is formed by an upper half and a lower half mated and connected together and which accommodates a disk on which data signals are recorded. A disk support is provided at least at one of the facing inner surfaces of the cartridge body corresponding to the non-signal recording region of the inner periphery of the disk. Disk support members with a high wear resistance and high lubricity are arranged spread in a ring at predetermined intervals at the surface of the disk support facing the disk.
The disk support members are formed as thin pieces and are joined to said disk support by an adhesive.
The disk support members used here are formed by sheet-like members of ultra-high molecular weight polyethylene or by sheet-like members of polyfluoroethylene fiber.
The disk support at which the disk support members are arranged has a substantially horseshoe shape having a cutaway portion at the side facing the recording and/or reproduction use opening formed in the cartridge body. The disk support members are arranged at a plurality of locations spread at equal intervals in the circumferential direction of the substantially horseshoe shaped support.
More specifically, the disk support members are arranged at five locations spread at equal intervals in the circumferential direction of said substantially horseshoe shaped support.
Further, the disk support members may be arranged at three locations spread at equal intervals in the circumferential direction of said substantially horseshoe shaped support.
Further, in the disk cartridge according to the present invention, the disk support members are arranged at the disk supports provided at the facing inner surfaces of the upper and lower halves.